Federal workers would be eligible for tax-deferred thrift/investment options such as those available to workers in top private-industry firms under pension bills Senate-House conferees will take up in the next few weeks.

Civil servants, whether they are in their twenties or sixties, have a stake in the outcome.

One proposal would allow civil servants to put up to 10 percent of their pay (with some matching from the government) into tax-deferred thrift plans similar to 401 (k) programs available to nonfederal workers. Typically, employes in firms with those plans put in about 10 percent of salary, with about 80 percent of the firms matching part of that.

Congress has until May 1 to set up a new retirement program for federal employes hired since January 1984. The new program would be mandatory for only those employes. Workers hired before January 1984 would not be required to participate in the new system, which most likely will base future retirement benefits on Social Security, a modified civil service benefit and the so-called thrift plan with contributions from employes and the government.

The Senate (by a 96-to-1 vote) has approved a new retirement plan that would give workers two options. One would provide a less generous civil service benefit but greater tax-deferred investment chances. The second option would give employes a bigger guaranteed civil service benefit with a less generous thrift plan. One Senate option would allow employes to retire without penalty at age 55 after 30 years of service.

In the other option, the retirement age would be 62. Persons hired since January 1984 would be required to join one of the two Senate plans. Workers hired before then could go into one of the options if they chose, or remain under the current civil service retirement program.

The House Post Office-Civil Service Committee has approved a single new retirement option. It would protect the right to retire at age 55 and would guarantee full cost-of-living raises for retirees (although Congress recently showed it can break such promises). The House bill would provide a better civil service benefit, but fewer investment options, than either Senate proposal. The House plan would be open only to workers hired since 1984.

Longtime federal employes -- who are not directly affected by the new pension system -- have a stake in it anyhow. That is because anything Congress sets up for new workers could later be imposed on longtime employes.